Field of the Invention
The present invention relates to a radiation image capturing apparatus. Specifically, the present invention relates to a radiation image capturing apparatus in which radiation detecting elements are aligned two dimensionally.
Description of Related Art
Various radiation image capturing apparatuses are developed. In such radiation image capturing apparatuses, charge is generated in a detecting element according to dose of radiation of irradiated X-ray, etc. and the generated charge is read out as image data. Such type of radiation image capturing apparatus is known as an FPD (Flat Panel Detector), and conventionally such apparatus was configured as a dedicated apparatus type (fixed type) formed as one with a supporting base, etc. Lately, a portable type (cassette type) radiation image capturing apparatus where the detecting element, etc. is stored in a case so that it can be carried is developed and being implemented.
Similar to a CR (Computed Radiography) cassette used in conventional radiation image capturing, such portable radiation image capturing apparatuses can be used for capturing in a state loaded on a bucky apparatus (see later described FIG. 4), held directly against a patient's body, or with the patient laid on the apparatus. The above features are features which dedicated apparatus type radiation image capturing apparatuses do not have.
However, when the radiation image capturing apparatus is used as described above in a state held directly against the patient's body or with the patient laid on the radiation image capturing apparatus, urine, blood, etc. of the patient may be attached to the radiation image capturing apparatus. When the urine, blood, etc. attached to the radiation image capturing apparatus infiltrates into the case of the apparatus, problems may occur such as a short circuit may occur or components may be damaged or broken in a sensor panel provided with electronic components, etc. (see later described SP of FIG. 2) in the case due to the infiltrated urine.
Therefore, Japanese Patent Application Laid-Open Publication No. 2012-181044 discloses a radiation image capturing apparatus configured to be provided with a waterproof member in a portion where a lid is fitted to a main body portion of a case so that the case includes a waterproof function.
When the waterproof performance of the radiation image capturing apparatus is enhanced by providing packing or a rubber or resin sealing member in a portion where a gap is formed in the case, hermetic performance of the case is also enhanced. However, when the highly airtight radiation image capturing apparatus is in an environment where outside pressure is low such as when used in facilities such as hospitals in highlands or when transported flying highly above in the air by aircraft, there is a difference between the pressure in the case (1 atmospheric pressure) and outside pressure (less than 1 atmospheric pressure).
When the case is strong enough to stand the pressure difference, expansion of the case can be suppressed. However, radiation image capturing apparatuses are usually thin, and the weight cannot be made heavy limitlessly. Therefore, in practice, it is difficult to make the case strong enough to stand the pressure difference. Therefore, the case of the radiation image capturing apparatus expands.
When the case of the radiation image capturing apparatus expands, the following problems may occur, such as, the packing, sealing, etc. provided to prevent the patient's urine, blood, etc. from infiltrating into the case of the radiation image capturing apparatus is removed or damaged, and the patient's urine, etc. is able to infiltrate into the case or the member in the apparatus is damaged or does not function properly due to the expansion of the case.
When the case of the radiation image capturing apparatus expands, the radiation image capturing apparatus cannot be loaded on the bucky apparatus, and capturing in a state loaded on the bucky apparatus may not be performed properly. Further, when the case of the radiation image capturing apparatus is used in an expanded state, the distance between the radiation detecting elements provided on the sensor panel in the case and the body of the patient which is the subject becomes far in the center portion of the radiation entering face (see later described R shown in FIG. 1 and FIG. 2) of the case expanded and rising and close in the periphery portion of the radiation entering face. Therefore, the image of the captured subject becomes an image with a blurred center portion, and the image cannot be suitably captured.